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Monday, February 04, 2013

Dreaming the Future: The Tennessee Valley Interstellar Workshop

The life of an enterprising space-geek writer is always
interesting, especially if said writer lives and works in a space-geek town
like Huntsville, Alabama. This past Saturday, I was attending the semi-monthly
Stammtisch (discussion group) at the home of Marshall Space Flight Center
Advanced Concepts engineer Les Johnson. Les is organizer of the Tennessee
Valley Interstellar Workshop (#TVIW13 on Twitter), a two-day gathering of
scientists, engineers, science fiction writers, and others interested in
sending humans or robots to other star systems.

As a preview of the event, Les had one of the speakers give
an informal version of his talk. Robert Kennedy, who works at a company called
The Ultimax Group, had a rather simple, but ambitious (and expensive) idea for
simultaneously reducing global warming and reducing our dependence on fossil
fuels. But first, a little background:

Les had an important ground rule for this talk: to reduce
the level of potential friction, for the purposes of Mr. Kennedy’s talk, we had
to stipulate that global warming was happening and focus instead on the ethical
implications of large-scale efforts to stop or mitigate it. For the most part,
the group (about 15 people) adhered to this.

So with this in mind, Kennedy and his coauthor Eric Hughes
started discussing the Intergovernmental Panel on Climate Change (IPCC) and
their findings related to global warming. IPCC has three primary committees:
one focusing on pure science (what’s going on), a second group focusing on
potential effects and economics of CC, and a third group—the most political and
controversial here in the U.S.—which concentrates on the political implications
of CC and what to do about it.

One potential solution to CC is something called
geoengineering—making large-scale changes to Earth’s environment to reduce
global temperatures. Some of the scarier proposals along this line come out of
Russia, including creating factories to belch large quantities of sulfur
compounds into the atmosphere; floating platforms in the ocean to generate
long-lasting clouds (thereby reflecting sunlight), and seeding the ocean with
iron oxide to encourage algal blooms and increase consumption of carbon
dioxide. The IPCC Annual Report 4 (AR4) made a one-paragraph mention of
geoengineering, promptly dismissing the idea. That hasn’t stopped people or
governments from thinking about it.

Kennedy proposed—prepare to be shocked—a space-based
solution for global warming. The idea? Build a massive solar array—a circle of
solar cells merely the size of Texas, place it between the sun and the Earth.
Still being a bit ignorant of such things, I asked an obvious question: “You’re
not blocking out the sun completely, are you?” The answer is no. Placed in a
stable orbital position (the Earth-Sun L1 Lagrange point), this array would
block ~0.1% of the solar energy striking the Earth. It’s rather like placing a
grain of sand in front of a flashlight. So what difference would that make? A
lot, it turns out. That .1% reduction in solar energy—insolation is the technical term—is about the same as the amount of
heating humanity is pumping into the atmosphere through energy production and
breathing.

On the reverse side of these solar cells—a microwave power
transmitter, which would provide electrical power through space to a receiving
station (or stations) on Earth. Want to know more? Stay tuned until 11:35 a.m.
Central Time, when Kennedy’s talk will be streaming.